Method of impregnating fibrous materials for building elements



L NOV. 20, 1934. KERDMANN 1,981,592

METHOD OF IMPREGNATING FIBROUS MATERIALS FOR BUILDING ELEMENTS Filed oci. 15. 1930 Fig.1

COMPOSITIONS,

COATING OR PLASTIC.

Patented Nov. 20, 1934 UNITED STATES METHOD OF IMPREGNATING FIBROUS MATERIALS FOR BUILDING ELEMENTS Konrad Erdmann, Radenthein, Austria Application October 15,

1930, Serial No. 488,938

In Austria February 19, 1930 1 Claim.

The invention relates to the manufacture of building elements from a fibrous material impregnated with a hardening binding agent, for instance of plates from wood wool hardened and 5 cemented together by means of sorel cement or other binders. For producing such plates wood wool is impregnated with an emulsion of the binding agent and then transferred into molds, where the setting takes place. For carrying out these operations in a more economical manner the molding is eiiected by means of a machine in such a manner, that by means of conveying bands or strips the fibrous material is shaped to a continuous body resembling a hank, then conveyed through a setting (drying and hardening) chamber and thereafter cut into plates. Manual work, however, is thus not completely but only partly eliminated as impregnating the fibrous material with the emulsion of the binding agent and introducing the impregnated material into the molds has still to the greatest part to be effected by hand. This is done by immerging the fibrous material into an emulsion of the binding agent and allowing the excess of the latter to drop off. The removal of the excess can be accelerated by subjecting the impregnated fibrous material to a suitable pressure between perforated metal sheets. Thereafter the mass is introduced by hand into the molds or into the above mentioned molding machine forming a hank therefrom.

It is the main object of the present invention to provide a method for mechanically impregnating the fibrous material with the emulsion in a continuous operation and in such manner, that the impregnated material is after the treatment obtained in the form of a hank having throughout a uniform structure.

According to the present invention this is realized in the following manner: The fibrous material is by introducing it into a shaft or hopper preliminarily shaped into a loose hank which by means of a pair of rollers mounted at the lower end of the said shaft is pulled on and simultaneously compressed; This hank is then pulled through an emulsion bath and at the outlet of the latter freed from the excess of emulsion by squeezing. The receptacle containing the emulsion has preferably the shape of a trough, through which the hank is conveyed so as to slide on its bottom. The conveying of the hank through the emulsion container is effected by two pairs of rollers or cylinders, the one pair of which is the above men- 55 tioned one which draws the material down within the shaft and pushes the hank into the trough, whilst the other pair, rotating at a higher speed, pulls the hank out of the trough. The hank is thus, while passing through the emulsion bath, drawn out in its longitudinal direction, which procedure is of importance for a good thorough covering and impregnation of the fibres. The pulling pair of rollers performs at the same time also the operation of freeing the hank from the excess of emulsion. This pair of rollers is so arranged, that the excess of emulsion squeezed out by them from the hank will flow back into the trough, and the one of these two rollers being so mounted as to work under the adjustable pressure of a weight for the purpose of accommodating the pressure to the density of the emulsion and thus applying the desired amount of emulsion, to the fibrous material.

Prior to being introduced into the molding machine the fibrous material pulled out from said trough by the squeezing rollers is subjected to a treatment whereby the squeezed material is loosened and then in the loosely and uniformly distributed state advanced to the molds or to the feeding conveyor at the entry end of the molding machine. According to an essential feature of the invention this loosening and forwarding operation is effected by means of flinging or tossing forks which are moved in an approximately elliptic path by a combined system of cranks and levers.

' By the forks portions of the material, that is clustered tufts, pads or bunches of equal size are torn off from the hank advanced at uniform speed and are thrown on to a conveyor likewise moving at a uniform speed, for instance on an endless belt constituting the feeding device of the molding machine. As the range of throw varies according to the mass of each single bunch, a uniform structure of the material when fed into the molding machine is obtained by this operation which may, if preferred, be repeated.

An apparatus suitable for carrying the invention into practice is illustrated in the accompanying drawing by way of example. Fig. 1 showing a sectional elevation on the line 2-2, Fig. 2; and Fig. 2, a plan view thereof.

The wood wool is fed into a straight vertical shaft 1, the bottom of which is constituted by parts of the peripheral surface of the rollers 2 and 3. The roller 2 is mounted in stationary bearings and driven by any suitable means, for instance by an electro-motor, in which case, as is shown, a worm gear is inserted between the motor and said roller 2.

The roller 3 is rotatably mounted at the ends of swinging arms 4 and driven by toothed wheels 6 which engage with toothed wheels 5 keyed to the shaft of the roller 2, the position of the axle of the roller 3 being such, that the plane passing through the axis of the rollers 3 and 2 is slanting. The upper roller 3 is thus movably mounted for the purpose of maintaining the pressure on the hank constant. Adjacent to and bearing against the rollers 2, 3 a trough 7 is fixed, into which the emulsion is continuously fed from a container 8 preferably provided with an adjustable outlet. The front edge of the trough bears against the lower roller of the squeezing roller pair 9, 10, which by means of sprocket wheels 11, 12 and an endless chain 13 is driven from the shaft of the roller 2. The ends of the shaft of the upper roller 10 are connected to the frame of the machine by means of horizontal links 14 and to weighted levers 16 by means of links 15. The pressure under which the excess of emulsion is squeezed out by the rollers 9, 10 can be adjusted by displacing the weights 17 along the levers 16. 18 is a track or channel with a curved bottom, the one end of which is closely near the squeezing and pulling rollers 9, 10. Through the space of this channel there pass the points of the flinging forks 20, which in staggered relation are pivotally connected to cranks 21 and at their ends to levers 22, the other end of the latter being journalled to the frame of the machine. The crank shaft 23 may be driven by any suitable means, for instance as shown, by a pulley and belt. By means of this driving arrangement a movement in an approximately elliptic path is imparted to the points of the flinging forks.

By the walls of the shaft 1 the introduced fibrous material is brought into the form of a loose hank. The rollers 2, 3 pull the hank thus formed out of the shaft 1 while simultaneously compressing it. Another function of these two rollers consists in pushing the hank so formed of the material under treatment along the bottom of the trough 7, which is partly filled with the emulsion. The rollers 9, 10 pull the hank out of the trough '7 at a speed higher than that, at which the rollers 2, 3 deliver it into the trough. Consequently the hank is drawn out and loosened while passing the trough whereby a perfect soaking, covering and impregnation of all the fibres is ensured. The excess of emulsion is squeezed out from the hank by the rollers 9, 10 and flows back into the trough 7. In the course of practical 30 operation of the machine it has been found, that a uniform squeezing is only effected when the diameter of at least one of the rollers 9, 10 is smaller in the middle than at the ends of the roller. The hank freed from the excess of emulsion does not have the same cross-section throughout nor does it have a perfectly uniform porous structure and therefore a more regular state has to be given to the material before it enters the molding machine. This is accomplished by the forks 20, which loosen the hank and throw the material in portions on to the conveyer 25 provided at the feeding end of the molding machine.

The bunches torn off by the forks from the hank are of equal size, whilst the action of the 9 air resistance on the bunches during their travel to the conveyer varies according to the mass of each bunch, so that the material is deposited on the conveyer in a more uniformly distributed state. This treatment of the hank by means of the fiinging forks may, if desired, be repeated several times.

It is an advantageous feature in the operation of the impregnating machine described hereinbefore that the hank slides along the bottom of the 10 trough, as the deposition of fibres having come 01f the bank or the deposition of hardened emulsion is thus prevented.

What I claim is:-

In the manufacture of highly porous stiff build- 1 ing elements the method of treating fibrous materials, by forming therefrom a slightly pressed hank, conveying the latter along the deepest place of an emulsion bath, drawing it out in the longitudinal direction while passing through the emulsion bath, squeezing the excess of emulsion out of said hank when leaving the bath, dividing the fibrous material of the hank into portions, flinging these portions further on and uniting them at a constant speed.

KONRAD ERDMANN. 

